Tank unit, ink jet recording head and method of manufacturing tank unit and ink jet recording head

ABSTRACT

A flow path forming member is formed with a recessed portion for forming an ink flow path. A junction surface of the flow path forming member is in a protruded state from a non-junction surface. The flow path forming member is composed of a transparent resin exhibiting transmissivity of laser beam. A tank holder is composed of a non-transmissive resin having no transmissivity of the laser beam. In a state where the flow path forming member is press-connected to the tank holder, the junction surface is welded by irradiating a periphery of the ink flow path with the laser beam from the side of the flow path forming member, thereby forming an ink flow path. Provided is an ink jet recording head in which the tank holder and the flow path forming member that serve to form the ink flow path are surely connected by a small number of steps without producing foreign matters within the ink flow path.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invent relates to an ink jet recording head of an ink jetrecording apparatus that performs recording by discharging inks.

2. Description of the Related Art

FIG. 17 shows an exploded perspective view for explaining a constructionof a conventional ink jet recording head. FIG. 18 shows a crosssectional view of a recording head cartridge in which an ink tank isinstalled in the ink jet recording head. FIGS. 19A through 19C showschematic sectional enlarged views for explaining a step of forming anink flow path.

An ink jet recording head 1020 shown in FIGS. 17 and 18 has hithertoused a method of assembling a tank holder unit 1200 byultrasonic-wave-welding an flow path forming member 1220 to a tankholder 1210 in order to form an ink flow path 1214 for guiding an ink inan ink tank 1040 to a recording element unit 1300 via the tank holder1201.

As shown in FIG. 18, in a state where the ink tank 1040 is installed inthe ink jet recording head 1020, the ink is supplied into the ink jetrecording head 1020 via a joint portion including a filter 1230 and aseal rubber 1240 from an ink supply port 1401 of the ink tank 1040. Theink is supplied to a recording element substrate 1330 of the recordingelement unit 1300 via the ink flow path 1214, and is then dischargedonto a recording sheet (unillustrated) by dint of energy generated byenergy elements (unillustrated) within a silicon substrate.

At this time, the ink flow path 1224 is formed by connecting the flowpath forming member 1220 to the tank holder 1210 by the ultrasonic wavewelding. To explain an assembling step with reference to FIGS. 19Athrough 19C, the tank holder 1210 is, as shown in FIG. 19A, formed witha groove serving as a burr reservoir 1218 in a connecting portion, whilethe flow path forming member 1220 is formed with a welding rib 1227 onthe connecting portion. As shown in FIG. 19B, the flow path formingmember 1220 is placed on the tank holder so that the welding rib 1227 isfitted into the groove of the burr reservoir 1218. Further, the flowpath forming member 1220 is pressed from above by an ultrasonic wavewelding horn 1054, and ultrasonic waves are oscillated while applying apressure. With the oscillations, as shown in FIG. 19C, the welding rib1227 spreads in the burr reservoir 1218 while being melted, and the tankholder 1210 and the flow path forming member 1220 are thus firmlyconnected together, thereby forming the ink flow path 1224.

Note that the numeral 1310 represents a first plate, 1311 designates anink supply port formed in the first plate, 1320 denotes a second plate,1330 stands for a recording element substrate, 1337 represents adischarge port formed in the recording element substrate, 1340 indicatesan electric wiring board, and 1341 designates an external signal inputterminal for electrically connecting the ink jet recording head to theink jet recording apparatus in FIGS. 17 and 18. The first plate 1311 isconnected to the flow path forming member 1220 and supports therecording element substrate 1330 and the second plate 1320 as well. Thesecond plate 1320 supports the electric wiring board 1340. These membersconstitute the recording element unit 1300.

SUMMARY OF THE INVENTION

The method described so far is a rational method as a means for surelyforming an airtight ink flow path in a short period of time at a lowcost. In the prior art described above, however, the burrs melted out ofthe welding rib 1227 by the oscillations of the ultrasonic waves bulgeover the ink flow path 1224 from the burr reservoir 12218, with theresult that fine resinous grains are fragmented into pieces of dusts andclog in the ink discharge port 1337 of the recording element substrate1330. This results in a discharge defect of the ink and might cause adecline of reliability on the ink jet recording head 1020.

For eliminating the dusts produced by the resin burrs, the ink flow path1224 is washed in a subsequent washing step. The burr reservoir 1218 isnot, however, all filled with the welded burrs, and a slight gap is leftand becomes a stagnated portion when flowing the wash water. Then, awashing pressure of the wash water is hard to be exerted, and aconsiderably long period of time is required for completely flowing thedusts away. This makes it impossible to reduce assembly time and is afactor for raising the costs.

Moreover, the flow path forming member 1220 is provided with a protrudedportion of the ultrasonic wave welding rib 1227, and the tank holder1201 is formed with the recessed portion as the burr reservoir 1218.Therefore, a gap between the adjacent ink flow paths must be set equalto or larger than approximately 1.5 mm. As a result, there arises suchinconvenience that the ink flow paths can not be disposed at a highdensity, and hence it is difficult to downsize the ink jet recordinghead.

On the other hand, Japanese Patent Application Laid-Open Publication No.8-183182 and U.S. Pat. No. 5,808,641 disclose technologies, wherein aresinous top board having a plurality of discharge ports and a pluralityof liquid flow paths and a substrate for generating discharge energy,are integrally welded by irradiation of the laser beams. Thesetechnologies prevent such inconvenience that liquid dischargeperformance is declined by a distortion caused on the resinous top boardand by resultant deformations of the liquid flow paths and the dischargeports as happened in the conventional method for making the resinous topboard and the substrate integral by pressing the resinous top boardagainst the substrate through an elastic member.

The sure welding of this resinous top board to the substrate, however,involves providing a resinous film on a welding surface on the substratebeforehand, and a resinous film adhering step therefor is incorporatedinto the substrate manufacturing step. This leads to an increase in thecost for the substrate.

It is an object of the present invention to provide an ink jet recordinghead, wherein a connection between a tank holder (which will hereinafteralso be called a “container holding member) for forming an ink flow path(which will hereinafter referred to also as a “liquid flow path”) and aflow path forming member, is conducted surely in a small number of stepsat a short interval between flow paths without producing foreign matterswithin the ink flow path.

According to one aspect of the present invention, an ink jet recordinghead comprises a container holding member to which a liquidaccommodating container for accommodating a liquid is attached, and aflow path forming member connected to the container holding member, anda plurality of liquid flow paths linked to the liquid accommodationcontainer are formed between the container holding member and the flowpath forming member that have been connected together. Further, at leastone of the container holding member and the flow path forming member isformed with a recessed portion for forming the liquid flow path, atleast one of a junction surface portion of the container holding memberand a junction surface portion of the flow path forming member has aprotruded portion assuming a protruded shape from non-connected surfacesof the members having the junction surface portions. Moreover, the flowpath forming member is composed of a resin exhibiting transmissivity oflaser beam, a non-transmissive material exhibiting none oftransmissivity of the laser beam exists in at least a junction area ofthe container holding member between the container holding member andthe flow path forming member, the non-transmissive material emits heatby irradiating a periphery of the ink flow path with the laser beam fromthe side of the flow path forming member in a state where the flow pathforming member is pressure-welded to the container holding member, andthe junction surface portion of the container holding member and thejunction surface portion of the flow path forming member are welded,thereby forming the liquid flow path.

According to another aspect of the present invention, there is provideda method of manufacturing an ink jet recording head comprising acontainer holding member to which a liquid accommodating container foraccommodating a liquid is attached, and a flow path forming memberconnected to the container holding member, wherein a plurality of liquidflow paths communicating with the liquid accommodation container areformed between the container holding member and the flow path formingmember that have been connected together. The ink jet recording headmanufacturing method comprises a preparing step of the container holdingmember and the flow path forming member, in which at least one of thecontainer holding member and the flow path forming member is formed witha recessed portion for forming the liquid flow path, at least one of ajunction surface portion of the container holding member and a junctionsurface portion of the flow path forming member has a protruded portionassuming a protruded shape from non-connected surfaces of the membershaving the junction surface portions, a press-connecting step ofpress-connecting the container holding member and the flow path formingmember in a state where a non-transmissive material exhibiting none oftransmissivity of the laser beam exists in at least a junction areabetween the container holding member and the flow path forming member,and a welding step of irradiating a periphery of the ink flow path withthe laser beam from the side of the flow path forming member composed ofa resin having transmissivity of the laser beam in a state where theflow path forming member and the container holding member arepress-connected to each other, thus heating the non-transmissivematerial, then welding the junction surface portion of the containerholding member and the junction surface portion of the flow path formingmember by this heating, and thus forming the liquid flow path.

At least one surface of the junction surfaces in the periphery of theportions formed with the liquid flow paths of the container holdingmember and of the flow path forming member, is formed in the protrudedshape from the non-junction surfaces. The flow path forming member iscomposed of the transparent resin having the transmissivity of the laserbeam. The non-transmissive material having no transmissivity of thelaser beam exists in at least the junction surface area of the containerholding member. In the state where the flow path forming member ispress-connected to the container holding member, the junction surface iswelded by irradiating the periphery of the liquid flow path with thelaser beam from the side of the flow path forming member, therebyforming the liquid flow path. The method, which is simple and attainedat a low cost, provides the ink jet recording head capable of designinga high-density layout of the liquid flow paths with neither occurrenceof the dusts of the resinous materials composing the container holdingmember and the flow path forming member nor formation of the stagnatedportion within the liquid flow path.

As described above, the present invention yields an effect that themethod, which is simple and attained at the low cost, enables theformation of the ink jet recording head capable of designing thehigh-density layout of the liquid flow paths with neither the occurrenceof the dusts of the resinous materials composing the container holdingmember and the flow path forming member nor formation of the stagnatedportion within the ink flow path.

The following is the reason for this. At least one surface of thejunction surfaces in the periphery of the portions formed with theliquid flow paths of the tank holder and of the flow path formingmember, is formed in the protruded state from the non-junction surfaces.The flow path forming member is composed of the transparent resin havingthe transmissivity of the laser beam. The non-transmissive materialhaving no transmissivity of the laser beam exists in at least thejunction surface area of the tank holder. In the state where the flowpath forming member is press-connected to the tank holder, the junctionsurface portions of the tank holder and of the flow path forming memberare welded by irradiating the periphery of the ink flow path with thelaser beam from the side of the flow path forming member, therebyforming the liquid flow path.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view showing a step of attaching aflow path forming member to a tank holder of an ink jet recording headin a first embodiment of the present invention;

FIG. 2 is a schematic perspective view showing a step of irradiating,with laser beams, the flow path forming member attached to the tankholder of the ink jet recording head in the first embodiment of thepresent invention;

FIGS. 3A and 3B are schematic side sectional views of FIGS. 1 and 2;FIG. 3A corresponds to FIG. 1; FIG. 3B corresponds to FIG. 2;

FIGS. 4A, 4B and 4C are schematic side surface partial sectional viewsshowing a step of bonding the flow path forming member to the tankholder of the ink jet recording head in the first embodiment of thepresent invention; FIG. 4A shows a relative relationship between thetank holder and the flow path forming member before being bonded; FIG.4B shows a state of irradiating the flow path forming member with thelaser beams in a way that abuts the flow path forming member on the tankholder; FIG. 4C shows a bonded state;

FIGS. 5A and 5B are perspective views of a recording head cartridge;FIG. 5A shows an assembled state; FIG. 5B shows a state where the inktanks are removed;

FIG. 6 is a perspective view of a tank holder unit and a recordingelement unit of the ink jet recording head;

FIG. 7 is a schematic exploded perspective view of the ink jet recordinghead;

FIG. 8 is a schematic partially cut perspective view of a recordingelement substrate constituting a recording element unit;

FIG. 9 is a schematic perspective view showing a relationship betweenthe ink jet recording head and the ink tanks;

FIG. 10 is a schematic sectional view of the recording head cartridge;

FIGS. 11A, 11B and 11C are schematic side surface partial sectionalviews showing a step of connecting the flow path forming member to thetank holder of the ink jet recording head in a second embodiment of thepresent invention; FIG. 11A shows a relative relationship between thetank holder and the flow path forming member before the connection; FIG.11B shows a state in which the flow path forming member is irradiatedwith the laser beam in a way that abuts the flow path forming member onthe tank holder; FIG. 11C shows a connected state;

FIGS. 12A, 12B and 12C are schematic side surface partial sectionalviews showing a step of connecting the flow path forming member to thetank holder of the ink jet recording head in a third embodiment of thepresent invention; FIG. 12A shows a relative relationship between thetank holder and the flow path forming member before the connection; FIG.12B shows a state in which the flow path forming member is irradiatedwith the laser beam in a way that abuts the flow path forming member onthe tank holder; FIG. 12C shows a connected state;

FIG. 13A is a sectional photo of an ink flow path when cut in adirection vertical to a direction in which a liquid flows within the inkflow path formed by utilizing conventional ultrasonic wave welding; FIG.13B is a sectional photo of the ink flow path when cut in a directionvertical to the direction in which the liquid flows within the ink flowpath formed by utilizing laser welding in the present embodiment;

FIG. 14 shows a conceptual diagram of an in-liquid particle measuringapparatus;

FIGS. 15A, 15B and 15C are schematic side surface partial sectionalviews showing a step of connecting the flow path forming member to thetank holder of the ink jet recording head in a fourth embodiment of thepresent invention; FIG. 15A shows a relative relationship between thetank holder and the flow path forming member before the connection; FIG.15B shows a state in which the flow path forming member is irradiatedwith the laser beam in a way that abuts the flow path forming member onthe tank holder; FIG. 15C shows a connected state;

FIGS. 16A, 16B and 16C are schematic side surface partial sectionalviews showing a step of connecting the flow path forming member to thetank holder of the ink jet recording head in a fifth embodiment of thepresent invention; FIG. 16A shows a relative relationship between thetank holder and the flow path forming member before the connection; FIG.16B shows a state in which the flow path forming member is irradiatedwith the laser beam in a way that abuts the flow path forming member onthe tank holder; FIG. 16C shows a connected state;

FIG. 17 is an exploded perspective view for explaining a construction ofan ink jet recording head in the prior art;

FIG. 18 is a cross sectional view of a recording head cartridge in whichan ink tank is installed in the ink jet recording head in the prior art;and

FIGS. 19A, 19B and 19C are schematic side surface partial sectionalviews showing a step of connecting the flow path forming member to thetank holder of the ink jet recording head in the prior art; FIG. 19Ashows a relative relationship between the tank holder and the flow pathforming member before the connection; FIG. 19B shows a state in which anultrasonic wave welding horn is oscillated in such a way that the flowpath forming member is made contiguous to the tank holder and is pressedfrom above by the ultrasonic wave welding horn; FIG. 19C shows aconnected state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described in detail withreference to the drawings.

FIG. 1 is a perspective view showing a step of attaching a flow pathforming member to a tank holder of an ink jet recording head in a firstembodiment of the present invention. FIG. 2 is a schematic perspectiveview showing a step of irradiating, with laser beams, the flow pathforming member attached to the tank holder of the ink jet recording headin the first embodiment of the present invention. FIGS. 3A and 3B areschematic side views of FIGS. 1 and 2. FIG. 3A corresponds to FIG. 1,while FIG. 3B corresponds to FIG. 2. FIGS. 4A, 4B and 4C are schematicsectional views of side surfaces, showing a step of bonding the flowpath forming member to the tank holder of the ink jet recording head inthe first embodiment of the present invention. FIG. 4A shows a relativerelationship between the tank holder and the flow path forming memberbefore being bonded. FIG. 4B shows a state of irradiating the flow pathforming member with the laser beams in a way that abuts the flow pathforming member on the tank holder. FIG. 4C shows a bonded state.

The discussion will start with explaining a construction of the ink jetrecording head in the first embodiment of the present invention and arelationship between related pieces of components such as a recordinghead cartridge, ink tanks, an ink jet recording apparatus body and acarriage. FIGS. 5 through 9 are explanatory views therefor. FIGS. 5A and5B are perspective views of the recording head cartridge. FIG. 5A showsan assembled state. FIG. 5B shows a state where the ink tanks areremoved. FIG. 6 is a perspective view of a tank holder unit and arecording element unit of the ink jet recording head. FIG. 7 is aschematic exploded perspective view of the ink jet recording head. FIG.8 is a schematic partially cut perspective view of a recording elementsubstrate constituting the recording element unit. FIG. 9 is a schematicperspective view showing a relationship between the ink jet recordinghead and the ink tanks. Configurations of the respective portions willhereinafter be explained with reference to the drawings.

An ink jet recording head 20 of the present invention is, as can beunderstood from the perspective views in FIGS. 5A and 5B, one componentconfiguring a recording head cartridge 10. The recording head cartridge10 is constructed of the ink jet recording head 20 and ink tanks 40 (41,42, 43, 44, 45, 46) defined as liquid accommodation containers soprovided as to be detachably attached to the ink jet recording head 20.This recording head cartridge 10 is fixedly supported by a positioningmeans and an electric contact of the carriage mounted on theunillustrated ink jet recording apparatus body, and is detachable fromand attachable to this carriage. The ink tank 41 is provided forcontaining a black ink. The ink tank 42 is for a light cyan ink. The inktank 43 is for a light magenta ink. The ink tank 44 is for a cyan ink.The ink tank 45 is for a magenta ink. The ink tank 46 is for a yellowink. Thus, the ink tanks 41, 42, 43, 44, 45 and 46 are each detachablyattached to the ink jet recording head 20 and also replaceable. Thisconstruction leads to a decrease in print running costs in the ink jetrecording apparatus. The recording head cartridge, the ink jet recordinghead, the ink tanks, the ink jet recording apparatus body and thecarriage, which are shown in FIGS. 5 through 9, have configurations towhich a variety of novel technologies established at a stage ofaccomplishing the present invention were applied, and hence the wholeconstruction will be described in a way that briefly explains theirconfigurations.

(1) Explanation of Inkjet Recording Head

The ink jet recording head 20 is an ink jet recording head classified asa side shooter type in a bubble jet system, wherein recording isconducted by use of an electro-thermal converting element for generatingthermal energy for producing film boiling for the ink in accordance withan electric signal.

The ink jet recording head 20 is, as shown in the exploded perspectiveview in FIG. 6, constructed of a recording element unit 300 and a tankholder unit 200. Further, as illustrated in the exploded perspectiveview in FIG. 7, the recording element unit 300 is constructed of arecording element substrate 330, a first plate 310, an electric wiringboard 340 and a second plate 320. Further, the tank holder unit 200 isconstructed of a tank holder 210 serving as a contained holding member,a flow path forming member 220, a filter 230 and a seal rubber 240.

(1-1) Recording Element Unit

FIG. 8 is a perspective view with some portion cut off in order toillustrate a configuration of the recording element substrate 330. Inthe recording element substrate 330, a thin film (layer) is formed of asilicon substrate 331 that is, e.g., 0.5 mm to 1 mm in thickness.Moreover, there are formed six rows of ink supply ports 332 configuredby elongate channel-like through-ports serving as flow paths for sixcolor inks, and electro-thermal converting elements 333 are arrayed rowby row in a cross pattern on both sides of each ink supply port 332. Theelectro-thermal converting element 333 and an electric wire of Al, etc.for supplying the electro-thermal converting element 333 with electricpower are formed by a film forming technology. Further, a bump 335 ofAu, etc. is provided on an electrode portion 334 for supplying theelectric wire with the electric power. Formation of the ink supply port332 involves effecting anisotropic etching by utilizing crystalorientations of the silicon substrate 331. If a crystal orientation<100> is given on a wafer surface and a crystal orientation <111> isgiven in a thicknesswise direction, etching at an angle of approximately54.7 degree advances based on the anisotropic etching of alkaline series(KOH, TMAH, hydrazine, etc.). The etching to a desired depth is attainedby utilizing this method. Further, an ink flow path wall 336 for formingthe ink flow path corresponding to the electro-thermal convertingelement 333 and a discharge port 337 are formed by a photolithographytechnique in the silicon substrate 331, and six discharge port trains338 corresponding to the six color inks are formed. Moreover, theelectro-thermal converting element 333 is provided facing the dischargeport 337, through which the ink supplied from the ink supply port 332 isdischarged in such a way that the electro-thermal converting element 333produces an air bubble.

The first plate 310 is composed of a material of, for instance, aluminum(Al₂O₃) having a thickness of 0.5 mm to 10 mm. The material of the firstplate 310 is not limited to alumina. The first plate 310 may be composedof a material exhibiting a linear expansion coefficient equal to alinear expansion coefficient of the material for the recording elementsubstrate 330 and a thermal conductivity equal to or larger than athermal conductivity of the material of the recording element substrate330. The material of the first plate 310 may be any one of, for example,silicon (Si), aluminum nitride (AlN), zirconium oxide (ZrO₂), siliconnitride (Si₃N₄), silicon carbide (SiC), molybdenum (Mo) and tungsten(W). The first plate 310 is formed with six pieces of ink supply ports311 for supplying the six color inks to the recording element substrate330. The six ink supply ports 332 of the recording element substrate 330correspond respectively to six pieces ink supply ports 311 in the firstplate 310, and the recording element substrate 330 is fixedly bondedwith a high positional accuracy to the first plate 310. A first bondingagent used for bonding is coated substantially in a shape of therecording element substrate over the first plate 310 so that none of airpaths are formed between the ink supply ports adjacent to each other. Adesirable bonding agent as the first bonding agent is, for instance, lowof its viscosity and thin of a bonding layer formed on a contactsurface, and exhibits comparatively high hardness after being hardenedand ink resistance as well. The first bonding agent is a thermosettingbonding agent composed mainly of, e.g., an epoxy resin, and it isdesirable that a thickness of the bonding layer be equal to or smallerthan 50 μm.

The electric wiring board 340 serves to apply a signal voltage fordischarging the ink to the recording element substrate 330. The electricwiring board 340 includes an aperture portion through which therecording element substrate 330 is built in, an electrode terminal(unillustrated) corresponding to the electrode portion 334 of therecording element substrate 330, and an external signal input terminal341 disposed at an end portion of this wire and serving to receive theelectric signal from the body apparatus. The electric wiring board 340and the recording element substrate 330 are electrically connected toeach other. A connection method thereof is that, for example, aftercoating a thermosetting bonding resin over between the electrode portion334 of the recording element substrate 330 and the electrode terminal ofthe electric wiring board 340, the electrode portion 334 of therecording element substrate 330 and the electrode terminal of theelectric wiring board 340 are batchwise heated and simultaneouslypressurized by a heat tool, and the thermosetting bonding resin is thushardened, whereby the electrode portion 334 and the electrode terminalare electrically batchwise connected. Further, in the case of using ananisotropic conductive bonding agent containing conductive particles,the thermosetting bonding resin is likewise available. The material ofthe electric wiring board 340 involves using, for instance, a flexiblewiring board having a 2-layered wiring structure in which a surfacelayer is covered with a resist film. Moreover, a reinforcing plate isbonded to the back surface of the external signal input terminal 341,thereby improving planarity of the portion of the external signal inputterminal 341. A material of the reinforcing plate involves the use ofheat resistive materials such as glass epoxy, aluminum, etc. that areeach 0.5 mm to 2 mm in plate thickness.

The second plate 320 is formed of a material of, for instance, aluminum(Al₂O₃) having a thickness of 0.5 mm to 1 mm. It should be noted thatthe material of the second plate 320 is not limited to aluminum. Thesecond plate 320 may be composed of a material exhibiting a linearexpansion coefficient equal to a linear expansion coefficient of each ofthe materials for the recording element substrate 330 and the firstplate 310 and also exhibiting a thermal conductivity equal to or largerthan a thermal conductivity of each of the substrate 330 and the plate310. Then, the second plate 320 takes a configuration having an apertureportion larger than a dimension of an external configuration of therecording element substrate 330 fixedly bonded to the first plate 310.Further, the recording element substrate 330 and the electric wiringboard 340 are boned to the first plate 310 by a second bonding agent sothat the substrate 330 and the board 340 can be electrically connectedin plane, and the back surface of the electric wiring board 340 isfixedly bonded by a third bonding agent. Moreover, the electric wiringboard 340, which is bonded to the second plate 320, is at the same timebent at one side surfaces of the first plate 310 and of the second plate320 and thus bonded to the side surface of the first plate 310 by thethird bonding agent. A bonding agent usable as the second bonding agentis, for instance, low of its viscosity and thin of a bonding layerformed on a contact surface, and exhibits ink resistance. Further, thethird bonding agent involves using a thermosetting bonding film composedmainly of, e.g., an epoxy resin and having a thickness of 10 to 100 μm.

The electric connecting portions between the recording element substrate330 and the electric wiring board 340 of the thus constructed recordingelement unit 300, are sealed by a first sealing agent and a secondsealing agent and thus protected from corrosion due to the inks and froman external impact. The first sealing agent seals mainly an outerperipheral portion of the recording element substrate 330, while thesecond sealing agent seals an edge of the aperture portion of theelectric wiring board 340. Moreover, the bent electric wiring board 340is further subjected to forming in accordance with a shape of the tankholder unit 200.

(1-2) Tank Holder Unit

The tank holder 210 is formed by, e.g., molding of a resin. It isdesirable to use, as this resinous material, a resinous material mixedwith 5% to 40% of a glass filler in order to improve a configurationalrigidity. The tank holder 210 holds the detachable/attachable ink tanks40, and has tank positioning pins, tank positioning holes, i.e., a firsthole, a second hole and a third hole with which a first pawl, a secondpawl and a third pawl are respectively engaged, and an aperture portionfor a prism employed for detecting an ink residual amount.

Further, the tank holder 210 includes an installation guide for guidingthe recording head cartridge 10 to an installing position of thecarriage of the ink jet recording apparatus body, an engagement portionfor fixedly installing the recording head cartridge 10 into the carriageby use of s head set lever, and X-, Y- and Z-abutting portions forpositioning in a predetermined installing position of the carriage.Moreover, the tank holder 210 has a terminal fixing portion forpositioning and thus fixing the portion of the external signal inputterminal 341 of the recording element unit 300, a plurality of ribs areprovided on the terminal fixing portion and along its periphery, therebystrengthening rigidity of the surface including the terminal fixingportion. Further, color-separation ribs for preventing the respectivecolors from being intermingled each other are provided incolor-separation spaces in which the respective ink tanks 41, 42, 43, 45and 46 are installed. Moreover, finger anti-slip portions are providedon the side surfaces of the tank holder 210, thereby improving ahandling property of the ink jet recording head 20. Further, as shown inFIG. 7, the tank holder 210 is formed with an ink flow path 214 forguiding the ink to the recording element unit 300 from the ink tank 40,wherein the ink flow path 214 is one component of the tank holder unit200 and was, according to the prior art, formed by ultrasonic-weldingthe flow path forming member 220. Furthermore, a filter 230 forpreventing dusts from entering from outside is joined by thermal weldingto a joint portion engaging with the ink tank 40, and a seal rubber 240for preventing evaporation of the ink from the joint portion isattached.

(1-3) Connection of Recording Element Unit and Tank Holder Unit

As shown in FIG. 6, the ink jet recording head 20 is completed byconnecting the recording element unit 300 to the tank holder unit 200.The connection is conducted in the following manner. A portion of theink supply port (the ink supply port 311 of the first plate 310) of therecording element unit 300 and a portion of the ink supply port (the inkflow path 224 of the flow path forming member 220), are fixedly bondedby coating a fourth bonding agent over there so that these ink supplyports communicate with each other. Further, other than the portions ofthe ink supply ports, several portions at which the recording elementunit 300 and the tank holder unit 200 abut on each other, are fixedlybonded by a fifth bonding agent. Desirable bonding agents as the fourthand fifth bonding agents exhibit the ink resistance, get hardened at anormal temperature and are flexible enough to withstand a linearexpansion difference between different types of materials. According tothe present embodiment, for example, a moisture absorption hardeningtype silicon bonding agent is used. Furthermore, the fourth bondingresin and the fifth bonding resin may be the same bonding agent.Moreover, when bonding the recording element unit 300 to the tank holderunit 200 with the fourth and fifth bonding agents, the recording elementunit 300 is positioned and thus fixed by use of a sixth bonding agent.It is, desirable that the sixth bonding agent be instantaneouslyhardened. According to the present embodiment, for instance, anultraviolet-ray hardening bonding agent is employed, however, otherbonding agents may also be available.

A portion of the external signal input terminal 341 of the recordingelement unit 300 is positioned and thus fixed to one side surface of thetank holder 210 by use of terminal positioning pins (two pieces) andterminal positioning holes (two pieces). A fixing method is, forinstance, such that a terminal connection pin provided on the tankholder 210 is fitted into a terminal connection hole provided in theperiphery of the external signal input terminal 341 of the electricwiring board 340, and the fixation is attained by terminally welding theterminal connection pin. Other fixing means may, however, be usable.

(2) Description of Recording Head Cartridge

FIG. 9 illustrates the way of installing the ink jet recording head 20constituting the recording head cartridge 10 and the ink tanks 41, 42,43, 44, 45, 46. Referring to FIG. 9, the ink tanks 41, 42, 43, 44, 45,46 contain the inks assuming the colors corresponding to the respectivetanks. Further, the individual ink tanks 40 are formed with ink supplyports 401 for supplying the ink jet recording head 20 with the inkscontained in the ink tanks. For example, the ink tank 41 is formed withthe ink supply port 401 through which the black ink in the ink tank 41is supplied to the ink jet recording head 20 in the state where the inktank 41 is installed in the ink jet recording head 20.

FIG. 10 is a sectional view of the recording head cartridge 10.Referring to FIG. 10, the recording element substrate 330 is provided onone side portion of the undersurface of the box-shaped ink jet recordinghead 20. Further, the ink jet recording head 20 is, as described above,provided with the joint portion. The joint portion is formed with theink flow path 214 extending toward the recording element substrate 330.A flow of the ink in the thus constructed recording head cartridge 10will be explained in a way that exemplifies the ink tank 41 for theblack ink. The ink in the ink tank 41 is supplied to the interior of theink jet recording head 20 via the ink supply port 401 of the ink tank 41and via the joint portion. The ink supplied to the interior of the inkjet recording head 20 is further supplied to the first plate 310 of therecording element unit 300 via the ink flow path 214 within the tankholder 210 and via the ink flow path 224 within the flow path formingmember 220. Then, the ink is supplied to the ink supply port 332 of therecording element substrate 330 from the first plate 310 and further toa bubbling chamber accommodating the electro-thermal converting elements333 and the discharge ports 337 of the recording element substrate 330.The ink supplied to the bubbling chamber is discharged out of thedischarge ports 337 toward a recording sheet defined as a recordedmedium by dint of thermal energy generated by the electro-thermalconverting elements 333.

First Embodiment of the Present Invention

Next, the construction and features of the ink jet recording headaccording to a first embodiment of the present invention, will bedescribed with reference to FIGS. 1 through 4C. In the thus-constructedink jet recording head 20 in the first embodiment of the presentinvention the tank holder 210 itself is molded of a resin containing adye stuff or a pigment that absorbs the laser beams in order to disposea non-transmissive material that does not transmit the laser beams in ajunction surface area between the flow path forming member 220 forforming the ink flow path 224 and the tank holder 210. On the otherhand, the flow path forming member 220 is molded of a resin thattransmits the laser beams, and only a junction surface 223 of the flowpath forming member 220 is a protruded portion taking a protruded shapeunlike other non-junction surfaces. Further, all the junction surfacesformed on the tank holder 210 and in the periphery of the portion formedwith the liquid flow path of the flow path forming member 220, take thesame planar shape.

According to the first embodiment, concretely, the material used for theflow path forming member is a transparent material that transmits thelaser beams and exhibits excellency in terms of the ink resistance. Thismaterial is transparent Noryl [TPN9221] of [GE Plastics] (GeneralElectric International Inc.). Further, black Noryl [SE1X] is adopted asa material of the tank holder. A material of the flow path formingmember can also involve using transparent Noryl [TN300].

Note that Noryl herein connotes modified polyphenylene ether or modifiedpolyphenylene oxide. Noryl is a resin developed by the General ElectricInternational Inc. given above and is a material acquired by modifyingpolyphenylene ether (polyphenylene oxide). Noryl belongs to a categoryof thermoplastic resins and has a highly resistive property against acidand alkaline. Transparent Noryl described above is Noryl containing noneof color materials.

According to the first embodiment, the ink flow path 224 is formed inthe flow path forming member 220, and a sectional configuration of theink flow path 224 is substantially a rectangle of which one sidecorresponds to the tank holder 210 in the connected state.

The following is a description of how the ink jet recording head in thefirst embodiment of the present invention is constructed. In theaforementioned ink jet recording head, as shown in FIG. FIGS. 1, 3A and4A, after the flow path forming member 220 has been attached to the tankholder 210 in an arrow direction, the flow path forming member 220 is,as illustrated in FIGS. 2, 3B and 4B, pressed by a press jig 53 havingtransmissivity of the laser beams, thereby hermetically connecting thejunction surfaces together. Thereafter, a laser irradiation machine 51irradiates the resin mold forming the tank holder 210 with the laserbeams, with the result that the laser-beam-absorptive dye stuff orpigment contained in the resin mold emits the heat to melt the resin.The heat emitted at this time exothermically melts also the flow pathforming member 220, whereby the junction surface 223 in the periphery ofthe ink flow path 224 is connected by welding as shown in FIG. 4C. Notethat a holder receiving board 52 in FIGS. 3A and 3B is a board forsustaining the tank holder 210 when melting the flow path forming memberto the tank holder.

Herein, the flow path forming member 220, as only the junction surfacethereof takes the protruded shape unlike other non-junction surfaces,improves its hermetic connectivity. Then, the melting heat of theexothermic resin of the tank holder 210 is efficiently transferred tothe mold resin of the flow path forming member 220, whereby the tankholder 210 and the flow path forming member 220 can be melted andconnected to each other. A melted portion 228 is produced on the weldedsurface between the tank holder 210 and the flow path forming member224, however, a large burr as seen in the prior art does occur in theink flow path 224.

Further, all the junction surfaces formed on the tank holder 210 and inthe periphery of the portion formed with the liquid flow path of theflow path forming member 220, take the same planar shape, and hence,when a distance between a light source of the laser beams and thejunction surface portion is set fixed, the periphery of the liquid flowpath can be all welded, thereby enabling the manufacturing costs to bedecreased.

According to the first embodiment, as described above, the material ofthe flow path forming member involves the use of transparent Noryl givenabove. In the case of other ink resistive resin such as a PPS(polyphenylenesulfide) material, however, this material does not welltransmit the laser beams, a junction strength of the welded portionbetween the tank holder and the flow path forming member wasinsufficient, and a sufficient mechanical strength of the flow pathforming member was not acquired. Moreover, the majority of other resinssuch as an ABS resin and polycarbonate having such a grade as to exhibithigh laser beam transmissivity, which are, i.e., suited to the laserwelding, were conversely inferior in terms of the ink resistance andinsufficient as the materials of the flow path forming member.

By contrast, in the case of utilizing transparent Noryl given above asthe material of the flow path forming member, the transparent Noryl welltransmits the laser beams, and therefore the tank holder and the flowpath forming member could be welded together at the sufficientlypreferable junction strength. Besides, the sufficient mechanicalstrength of the flow path forming member was acquired. Further, thesufficient ink resistance was obtained.

Second Embodiment of the Present Invention

Next, a construction and features of the ink jet recording headaccording to a second embodiment of the present invention will beexplained with reference to FIGS. 11A, 11B and 1C. FIGS. 11A, 11B and11C are schematic side surface partial sectional views showing a step ofconnecting the flow path forming member to the tank holder of the inkjet recording head in the second embodiment of the present invention.FIG. 11A shows a relative relationship between the tank holder and theflow path forming member before the connection. FIG. 11B shows a statein which the flow path forming member is irradiated with the laser beamin a way that abuts the flow path forming member on the tank holder.FIG. 11C shows a connected state. The same members as those in the firstembodiment are marked with the same reference numerals.

In FIGS. 11A to 11C, the materials composing the flow path formingmember 220 and the tank holder 211 are the same as those in the firstembodiment. In the first embodiment, only the junction surface 223 ofthe flow path forming member 220 is formed as the protruded portiontaking the protruded shape unlike other non-junction surfaces. Accordingto the second embodiment, however, in both of the tank holder 211 andthe flow path forming member 220, respective junction surfaces 216 and223 thereof are formed as protruded portions each taking the protrudedshape unlike other non-junction surfaces.

In the second embodiment also, the ink flow path 224 is formed in theflow path forming member 220, and a sectional configuration of the inkflow path 224 is substantially a rectangle of which one side correspondsto the tank holder 211 in the connected state.

The following is a description of how the ink jet recording head in thesecond embodiment of the present invention is constructed. In theaforementioned ink jet recording head, as shown in FIG. 11A, after theflow path forming member 220 has been attached to the tank holder 211 inan arrow direction, the flow path forming member 220 is, as illustratedin FIG. 11B, pressed by the press jig 53 having the transmissivity ofthe laser beams, thereby hermetically connecting the junction surfacestogether. Thereafter, the laser irradiation machine 51 irradiates theresin mold forming the tank holder 211 with the laser beams, with theresult that the laser-beam-absorptive dye stuff or pigment contained inthe resin mold emits the heat to melt the resin. The heat emitted atthis time exothermically melts also the flow path forming member 220,whereby the junction surfaces 216, 223 in the periphery of the ink flowpath 224 are connected by welding as shown in FIG. 11G.

Herein, the tank holder 211 and the flow path forming member 220, asonly the junction surfaces thereof take the protruded shapes unlikeother non-junction surfaces, improve their hermetic connectivity. Then,the melting heat of the exothermic resin of the tank holder 211 isefficiently transferred to the mold resin of the flow path formingmember 220, whereby the tank holder 211 and the flow path forming member220 can be melted and connected to each other.

Third Embodiment of the Present Invention

Next, a construction and features of the ink jet recording headaccording to a third embodiment of the present invention will beexplained with reference to FIGS. 12A, 12B and 12C. FIGS. 12A, 12B and12C are schematic side surface partial sectional views showing a step ofconnecting the flow path forming member to the tank holder of the inkjet recording head in the third embodiment of the present invention.FIG. 12A shows a relative relationship between the tank holder and theflow path forming member before the connection. FIG. 12B shows a statein which the flow path forming member is irradiated with the laser beamin a way that abuts the flow path forming member on the tank holder.FIG. 12C shows a connected state. The same members as those in the firstembodiment are marked with the same reference numerals.

In FIG. 12, the materials composing a flow path forming member 221 and atank holder 212 are the same as those in the first embodiment. Further,as in the first embodiment, only a junction surface 223 of the flow pathforming member 221 is formed as the protruded portion taking theprotruded shape unlike other non-junction surfaces.

In the first and second embodiments, the ink flow path 224 is formed inthe flow path forming member 220, and a sectional configuration of theink flow path 224 is substantially a rectangle of which one sidecorresponds to the tank holder 212 in the connected state. According tothe third embodiment, the tank holder 212 and the flow path formingmember 221 are formed respectively with ink flow paths 214 and 225 eachtaking a semi-circular shape, wherein an ink flow path 215 taking acircular shape in section in the connected state is configured and showsa symmetrical shape in section with respect to the junction surface 223as a central surface. As shown in FIG. 12A, after the flow path formingmember 221 has been attached to the tank holder 212 in an arrowdirection, the flow path forming member 221 is, as illustrated in FIG.12B, pressed by the press jig 53 having the transmissivity of the laserbeams, thereby hermetically connecting the junction surfaces together.Thereafter, the laser irradiation machine 51 irradiates the resin moldforming the tank holder 212 with the laser beams, with the result thatthe laser-beam-absorptive dye stuff or pigment contained in the resinmold emits the heat to melt the resin. The heat emitted at this timeexothermically melts also the flow path forming member 221, whereby thejunction surfaces in the periphery of the ink flow path 215 areconnected by welding as shown in FIG. 12C.

Herein, as only the junction surface of the flow path forming member 221takes the protruded shape unlike other non-junction surfaces, thehermetic connectivity between the tank holder 212 and the flow pathforming member 221 is improved. Then, the melting heat of the exothermicresin of the tank holder 212 is efficiently transferred to the moldresin of the flow path forming member 221, whereby the tank holder 212and the flow path forming member 221 can be melted and connected to eachother.

Moreover, the ink flow paths formed in the tank holder 212 and the flowpath forming member 221 take the semi-circular shape in section and showthe symmetrical shape in section with respect to the junction surface asthe central surface. Accordingly, the combined ink flow path assumessubstantially the circular shape in section, whereby the ink flow path215 with no stagnated portion can be formed.

Interiors of the ink flow paths of the respective tank holder unitassembled by the conventional ultrasonic wave welding and by the laserwelding in the third embodiment were solidified by a resin, cut andpolished, and sections of the ink flow paths were observed. FIG. 13A andFIG. 13B respectively show microscopic photos thereof.

FIG. 13A shows the section of the ink flow path formed by the ultrasonicwave welding as the conventional method.

An example by the conventional method is that, the ultrasonic wavewelding property being taken into consideration, the flow path formingmember and the tank holder are formed of the same resinous material, andblack Noryl [PCN2910] of [GE Plastics] (General Electric InternationalInc.) is adopted as a material exhibiting the excellency of the inkresistance.

As can be recognized from the sectional photo in FIG. 13A, it isobserved that pointed prickled burrs 1229 occur due to the ultrasonicwave vibrations when welding, and a glass filler having a diameter of 13μm, which is added to the plastic also projects and is on the verge offalling out.

The reason for this is that when the flow path forming member 1220 iswelded to the tank holder 1210, the two members rub against each otherdue to the ultrasonic wave vibrations, and the resin melted by thefriction heat and the glass filler, etc. contained in the resin arescattered over the contact portion.

Further, a large amount of melted burrs 1229 are generated in theultrasonic wave welding, and hence there is a necessity of providing anextensive burr reservoir portion 1218 so that the melted burrs do notlargely extend over the ink flow path 1224, and this becomes the inkstagnated portion. The dusts occurred when in the ultrasonic wavewelding are easy to stagnate and are very hard to be removed in asubsequent washing step.

FIG. 13B shows a sectional photo of the tank holder unit when cut in adirection vertical to the liquid flowing direction within the ink flowpath formed by utilizing the laser welding in the present example.

Even in the case of the laser welding, a welding burr 229 is formedslightly. As the flow path forming member 221 is just pressed againstthe tank holder 212, a welding burr 229 takes a small round protrudedshape protruding from the junction surface, and the ink flow path 214 issubstantially circular in sectional shape. Thus, the welding burr 229assuming the small round protruded shape does not easily fall out, andit is therefore possible to remarkably reduce the dusts generated whenassembled.

Then, the laser-welding-based formation of the ink flow path involves asmall amount of melted burrs generated, and hence it is feasible toeliminate the burr reservoir that turns out to be the ink stagnatedportion, which was indispensable for the assembly based on theultrasonic wave welding.

For verifying an effect that the tank holder unit formed by the laserwelding has a smaller and less amount of generated dusts than by thetank holder unit formed by the conventional ultrasonic wave welding, theink flow paths of the tank holder units assembled by the ultrasonic wavewelding and by the laser welding are washed by alkaline wash water of aPH of 11.0, and the dusts contained in the wash drainage water areobserved by an particle in-liquid counter made by Rion Inc. FIG. 14shows a conceptual diagram of the in-liquid particle measuringapparatus.

The number of dusts is measured (counted) such that part (25 cc/min) ofthe wash drainage water flowing at a rate of approximately 4.5 l/min,which has been bifurcated from a drainage hose of a wash jig, isintroduced into the particle in-liquid counter, and a 1-sec dust countis detected at an interval of 3 sec on a time base for one minute sincethe washing was started.

Table 1 shows a comparison in total value between the dust counts of thedusts generated in the tank holder unit formed based on the ultrasonicwave welding shown in FIG. 13A and in the tank holder unit formed basedon the laser welding according to the third embodiment shown in FIG.13B. TABLE 1 Ultrasonic Wave Particle Size of Dust Welding Laser WeldingLess than 2 μm 846 pieces 742 pieces Equal to or larger than 92 pieces83 pieces 2 μm but less than 5 μm Equal to or larger than 5 pieces 0 5μm but less than 10 μm Equal to or larger than 1 piece 0 10 μm but lessthan 15 μm Equal to or larger than 0 0 15 μm but less than 20 μm Equalto or larger than 0 0 20 μm but less than 25 μm

The dust count of the dusts less than 5 μm in the laser welding issmaller by approximately 10% than in the ultrasonic wave welding.Further, none of the dusts having a particle size equal to or largerthan 5 μm are recognized in the laser welding, whereas in the ultrasonicwave welding the dusts having a particle size equal to or larger than 5μm but less than 15 μm are recognized.

It can be understood from this comparison that the dust generation canbe made less by assembling the tank holder unit based on the laserwelding than by the assembly based on the conventional ultrasonic wavewelding step.

On the other hand, a tendency over the recent years is that an arealsize of the discharge port for discharging the ink is decreased forreducing a volume of a liquid droplet discharged from the recording headas a method for performing the high-definition ink jet record. As aminimum diameter of the discharge port becomes smaller, a defectivedischarge caused by the discharge port which is clogged by the dusts inthe ink flow path becomes easier to occur. Therefore, according to theexperimental result given above, the formation of the liquid flow pathbased on the laser welding of the present invention can be, it isunderstood, preferably utilized in the case of using the recording headhaving the discharge port of which the minimum diameter is equal to orlarger than 5 μm but less than 15 μm, especially the recording headhaving the discharge port of which the minimum diameter is equal to orlarger than 5 μm but less than 10 μm.

Fourth Embodiment of the Present Invention

Next, a construction and features of the ink jet recording headaccording to a fourth embodiment of the present invention will beexplained with reference to FIGS. 15A, 15B and 15C. FIGS. 15A, 15B and15C are schematic side surface partial sectional views showing a step ofconnecting the flow path forming member to the tank holder of the inkjet recording head in the fourth embodiment of the present invention.FIG. 15A shows a relative relationship between the tank holder and theflow path forming member before the connection. FIG. 15B shows a statein which the flow path forming member is irradiated with the laser beamin a way that abuts the flow path forming member on the tank holder.FIG. 15C shows a connected state. The same members as those in the firstembodiment are marked with the same reference numerals.

In FIGS. 15A to 15C, the tank holder 210 as well as the flow pathforming member 220 are molded of transparent Noryl of the GeneralElectric International Inc. that is used as a material of the flow pathforming member 220 in each of the embodiments discussed above.

Further, as in the first embodiment, only the junction surface 223 ofthe flow path forming member 220 is formed as the protruded portiontaking the protruded shape unlike other non-junction surface.

According to the fourth embodiment, a laser beam absorptive coatingmaterial 226 having no transmissivity of the laser beams is coated overthe junction surface 223 so that a non-transmissive material is disposedin a junction surface area with the tank holder 210 for forming the inkflow path 224.

According to the fourth embodiment, as in the first and secondembodiments, the ink flow path 224 is formed in the flow path formingmember 220, and a sectional configuration of the ink flow path 224 issubstantially a rectangle of which one side corresponds to the tankholder 210 in the connected state.

After the laser beam absorptive coating material 226 composed of acoating material or a pigment that absorbs the laser beams has been, asshown in FIG. 15A, coated over the junction surface 223 of the flow pathforming member 220, the flow path forming member 220 is attached to thetank holder 210 in an arrow direction. Thereafter, as shown in FIG. 15B,the flow path forming member 220 is pressed by the press jig 53 havingthe transmissivity of the laser beams, thereby hermetically connectingthe junction surfaces together. Thereafter, the laser irradiationmachine 51 emits the laser beams, with the result that the laser beamabsorptive coating material 226 coated over the junction surface of theflow path forming member 220 emits the heat. Then, the resins of thetank holder 210 and of the flow path forming member 220, which arebrought into contact with the laser beam absorptive coating 226, arealso exothermically melted, whereby the junction surface 223 in theperiphery of the ink flow path 224 is connected by welding as shown inFIG. 15C.

Herein, as only the junction surface of the flow path forming member 220takes the protruded shape unlike other non-junction surfaces, the laserbeam absorptive coating material can be coated over only the junctionsurface, and the exothermic laser beam absorptive coating material emitsthe heat only on the junction surface between the mold resin of the tankholder 210 and the mold resin of the flow path forming member 220. Thesemold resins are thereby melted each other and can be connected throughresiduals of the laser beam absorptive coating material.

According to the fourth embodiment, the tank holder 210 and the flowpath forming member 220 can be formed of the same resin, and it ispossible to avoid an influence caused due to a difference in thermalexpansion between the resins at the junction surfaces.

The description in the fourth embodiment is that only the junctionsurface of the flow path forming member 220 takes the protruded shape,however, the junction surface of the tank holder 210 or the junctionsurfaces of the both may also be formed in the protruded shape. In thiscase, the laser beam absorptive coating material may be coated over thejunction surface of the tank holder 210.

Fifth Embodiment of the Present Invention

Next, a construction and features of the ink jet recording headaccording to a fifth embodiment of the present invention will beexplained with reference to FIGS. 16A, 16B and 16C. FIGS. 16A, 16B and16C are schematic side surface partial sectional views showing a step ofconnecting the flow path forming member to the tank holder of the inkjet recording head in the fifth embodiment of the present invention.FIG. 16A shows a relative relationship between the tank holder and theflow path forming member before the connection. FIG. 16B shows a statein which the flow path forming member is irradiated with the laser beamin a way that abuts the flow path forming member on the tank holder.FIG. 16C shows a connected state. The same members as those in the firstembodiment are marked with the same reference numerals.

In FIGS. 16A to 16C, the flow path forming member 220 and the tankholder 211 are composed of the same materials as those in the firstthrough third embodiments. Further, as in the second embodiment, onlythe junction surfaces of both of the tank holder 211 and the flow pathforming member 220 are protruded surfaces taking the protruded shapeunlike other non-junction surfaces. Moreover, according to the fifthembodiment, as in the first, second and fourth embodiments, the ink flowpath 224 is formed in the flow path forming member 220, and a sectionalconfiguration of the ink flow path 224 is substantially a rectangle ofwhich one side corresponds to the tank holder 211 in the connectedstate. In the fifth embodiment, the protruded surface serving as thejunction surface of the tank holder 211 is a junction surface 217subjected to a roughing surface treatment of making the surface rougherthan other non-junction surfaces.

After the flow path forming member 220 has been attached to the tankholder 211 in an arrow direction as shown in FIG. 16A, the flow pathforming member 220 is pressed by the press jig 53 having thetransmissivity of the laser beams as shown in FIG. 16B, therebyhermetically connecting the junction surfaces together. Thereafter, thelaser irradiation machine 51 emits the laser beams, with the result thatthe laser-beam-absorptive dye stuff or pigment contained in the resinmold forming the tank holder 211 emits the heat to melt the resin. Theheat emitted at this time exothermically melts also the flow pathforming member 220, whereby the junction surfaces 217, 223 in theperiphery of the ink flow path 224 are connected by welding as shown inFIG. 16C.

Herein, in the tank holder 211 and the flow path forming member 220,only the junction surfaces 217, 223 thereof are the protruded surfacestaking the protruded shapes unlike other non-junction surfaces, and thejunction surface 217 of the tank holder 211 is subjected to the roughingsurface treatment for roughing the surface. Therefore, the roughed andelevated (protruded) surface contiguous to the flow path forming member220 is melted in a short period of time, resulting in a melted contactsurface of the flow path forming member 220. Then, the mold resins canbe, with the roughed and elevated surface being centered, melted eachother and firmly connected.

In above embodiments of the Present Invention, the flow path formingmember is composed of a resin exhibiting transmissivity of laser beam.And by irradiating a periphery of the ink flow path with the laser beamfrom the side of the flow path forming member, the junction surfaceportion of the tank holder and the junction surface portion of the flowpath forming member are welded.

It may be carried out, however, that the tank holder member is composedof a resin exhibiting transmissivity of laser beam, and the tank holderand the flow path forming member are welded by irradiating a peripheryof the ink flow path with the laser beam from the side of the tankholder.

This application claims priority from Japanese Patent Application No.2003-295314 filed Aug. 19, 2003, which is hereby incorporated byreference herein.

1. An ink jet recording head comprising: a container holding member towhich a liquid accommodating container for accommodating a liquid isattached; and a flow path forming member connected to said containerholding member, wherein a plurality of liquid flow paths communicatingwith said liquid accommodating container are formed between saidcontainer holding member and said flow path forming member that havebeen connected together, wherein at least one of said container holdingmember and said flow path forming member is formed with a recessedportion for forming said liquid flow path, wherein at least one of ajunction surface portion of said container holding member and a junctionsurface portion of said flow path forming member has a protruded portionassuming a protruded shape from non-connected surfaces of said membershaving said junction surface portions, and wherein said flow pathforming member is composed of a resin exhibiting transmissivity of laserbeam, wherein a non-transmissive material exhibiting none oftransmissivity of the laser beam exists in at least a junction area ofsaid container holding member between said container holding member andsaid flow path forming member, wherein the non-transmissive materialemits heat by irradiating a periphery of said ink flow path with thelaser beam from the side of said flow path forming member in a statewhere said flow path forming member is pressure-welded to said containerholding member, and wherein said junction surface portion of saidcontainer holding member and said junction surface portion of said flowpath forming member are welded, thereby forming said liquid flow path.2. An ink jet recording head according to claim 1, wherein a materialcomposing said flow path forming member is modified polyphenylene ethercontaining none of color materials.
 3. An ink jet recording headaccording to claim 1, wherein said container holding member and saidflow path forming member respectively have said protruded portions. 4.An ink jet recording head according to claim 1, wherein said liquid flowpath takes substantially a circular shape in section vertical to adirection in which a liquid flows within said liquid flow path.
 5. Anink jet recording head according to claim 1, further comprising arecording portion having a discharge port communicating with said liquidflow path and serving to discharge an ink, wherein a minimum diameter ofsaid discharge portion is equal to or larger than 5 μm but less than 15μm.
 6. An ink jet recording head according to claim 5, wherein theminimum diameter of said discharge portion is equal to or larger than 5μm but less than 10 μm. 7.-8. (canceled)
 9. An ink jet recording headaccording to claim 1, wherein said container holding member is composedof said non-transmissive material. 10.-19. (canceled)